Induction of anesthesia can be accomplished with intravenous or inhalational anesthetic agents, which have both desired and side effects. The aim of this study was to record, investigate and compare the hemodynamic profile of five different induction anesthetic agents in patients undergoing major vascular surgery. One hundred and fifty patients, who were scheduled for major vascular surgery, were randomly assigned into five groups according to the anesthetic agent that was used for anesthesia induction. The five agents used for anesthesia induction were: propofol [2mg/kg], thiopental [3mg/kg], etomidate [0.3mg/kg], midazolam [0.2mg/kg] and diazepam [0.3mg/kg]. Before induction of anesthesia patients were administered Ringer lactate to replace volume deficit due to preoperative fasting. Besides standard intraoperative monitoring, an arterial catheter and a pulmonary artery catheter were placed in all patients before anesthesia induction. Continue reading
Central venous pressure (CVP) measurement along with invasive arterial pressure measurement are the two most widely used monitoring parameters in the Intensive Care Unit (ICU) and in the operating room (OR).In contrast with left heart catheterization, right heart catheterization is a procedure which is performed in the daily clinical practice both in the OR and the ICU and with which all anesthesiologists are well familiarized. Despite the limited usefulness of absolute CVP values, analysis of the CVP waveform offers important information regarding patient’s underlying pathology.ECG tracing should be taken concurrently with CVP measurement and CVP should be evaluated and interpreted in relationship to the ECG. CVP values are affected by several parameters such as mechanical ventilation and PEEP application, which should be taken into account when interpreting CVP measurements.
Tricuspid regurgitation (TR) is a relatively common abnormality and in most of the cases it is asymptomatic and has no clinical significance. In regard to etiology, TR can be categorized as primary (or organic) and secondary (or functional).TR allows blood to flow backwards across the valve from the right ventricle to the right atrium during right ventricle systole. When blood backflow is significant there may be giant systolic V waves in the CVP waveform. In case of severe TR, the giant systolic V waves are so prominent that the CVP waveform resembles the right ventricular pressure contour. This is called ventricularization of the right atrial pressure waveform. In contrast with the giant V waves in the CVP waveform, ventricularization of the right atrial pressure waveform is the most specific diagnostic criterion of severe TR. TR disease is diagnosed and thoroughly evaluated by echocardiography, which can give us information about its etiology and severity. However, CVP waveform may be indicative of TR and therefore could trigger further investigation and evaluation by echocardiography. Continue reading
Η βελτίωση των χειρουργικών τεχνικών αλλά κυρίως των χημειοθεραπευτικών σχημάτων αύξησε κατά πολύ την επιβίωση των ασθενών με κακοήθη νόσο των πνευμόνων. Οι ασθενείς που έχουν υποβληθεί σε θωρακοχειρουργική επέμβαση για κακοήθη νόσο πνευμόνων, έχουν αυξημένη πιθανότητα να υποβληθούν σε μια νέα διαγνωστική ή θεραπευτικήεπέμβαση, λόγω υποτροπής της αρχικής νόσου, ή εμφάνισης ενός δεύτερου πρωτοπαθούς όγκου του πνεύμονα. Continue reading
Increased IAP often coexists with sepsis in severely ill patients in the ICU, under mechanical ventilation and pharmaceutical support of the circulation with inotropes and vasoactive drugs. Both conditions have an unfavorable effect on the cardiovascular system. The purpose of this experimental study was to record the effect of increased intra-abdominal pressure on the cardiovascular system of pigs, with or without additional sepsis. Sixteen male pigs were randomly assigned in two groups A and B. In both groups, after induction to anesthesia and mechanical ventilation, the intra-abdominal pressure was increased to 25mmHg by helium insufflation in the peritoneal cavity, and that level of IAP was preserved until the end of the experiment. In Group A no other intervention apart from the increase in IAP was made, whereas in Group B, 60 minutes after the increase in IAP, 100μg/kg LPS were administered. Data were recorded after induction of anesthesia and initiation of mechanical ventilation (baseline measurement/measurement 0) and thereafter every 20 min after intra-abdominal pressure increase. The last measurement (measurement 9) was obtained immediately before release of pneumoperitoneum. Parameters measured or calculated included HR, BP(s,d,m), RVPs, PAP(s,d,m), PΑWP, CO, SV, SVR, PVR, SvO2, ETCO2. HR increased statistically significantly only in Group B, 60 minutes after the administration of LPS. BP (s, d, m) presented a significant change only in Group B, an initial increase immediately after LPS administration, followed by a decrease. CVP, RVPs and PAP (s, d, m) increased in both groups after IAP increase, whereas they presented an additional increase in Group B, after LPS administration. PΑWP changed only in Group B, after LPS administration. CO and SV were dramatically reduced in Group B, immediately after LPS administration, but gradually recovered their initial values until the end of the experiment. SVR changed only in Group B. They increased after LPS administration and then they gradually decreased. PVR increased dramatically after LPS administration and, despite gradual decrease they remained at high values until the end of the experiment. SvO2 decreased in Group B after LPS administration but gradually recovered its initial values. At the conditions of this particular experiment, the increase in intra-abdominal pressure was well tolerated by the laboratory animals. On the contrary, sepsis induction by LPS administration had an unfavorable effect on the cardiovascular system. Continue reading
The deficiency of the natural heart pacemaker, the conduction disturbances and the appearance of arrhythmias are common complications after cardiac surgery. Placement of epicardiac electrodes (ventricular, atrial, or both) during cardiac surgery remains common practice, even though few patients will actually need some kind of temporary epicardiac pacing for various periods of time. Temporary epicardiac pacing may be ventricular, atrial or atrioventricular, depending on the specific features of each patient and it aims at preserving the cardiac rhythm, securing the desired heart rate and achieving an acceptable cardiac output. Temporary epicardiac pacing is not without danger, since, under specific circumstances, it may have a negative impact on the hemodynamics of the patient, to the point of circulatory collapse. It may also cause ventricular tachycardia (R on T phenomenon) and cardiac arrhythmias (if pacing is not synchronized to the heart’s natural pacemaker). Ventricular Pacing and Sensing (VVI) is accomplished by the placement of electrodes only on the ventricles, which a priori means a certain degree of hemodynamic compromise, due to the loss of atrial contribution in preserving cardiac output. In certain occasions, this impact may be even more significant. This case report concerns a patient who underwent Coronary Artery Bypass Grafting (CABG) and after placement of the electrodes of temporary epicardiac ventricular pacing he presented significant decrease in systemic arterial pressure and the appearance of cannon A waves on central venous pressure (CVP) tracing every time the pacemaker was triggered. These phenomena, which receded after the disconnection of the pacemaker, consists a case of Pacemaker Syndrome.This problem was solved by adjusting the pacemaker’s frequency at a rate lower than that of the patient’s natural pacemaker. Continue reading